It should give more HP because the equivalence mythic averages your MP and HP even if you have flat HP on the mythic gear. This means you add HP and MP together and divide by 2 for equivalence. Without the mythic, you are not averaging HP/MP.
Let's pretend your HP is 10000 and MP is 3100.
With equivalece your HP would become (10000+3100)/2 = 6,550
Even removing 1 plagued set from 7 to 6 and losing 1 flat HP will give you 35% more HP because of how equivalence averages HP and MP in your exact build.
Hope that shed a little more light.I might make an update to my thread about accurately calculating HP/MP.